There are many known welding-type power supplies used for many known applications. Often, a particular power supply will have a topology and a control scheme chosen or optimized for particular welding applications. For example, a welding power supply might be designed for CV welding, AC welding, CC welding, or controlled short circuit (CSC) welding. Welding-type power supply, as used herein, includes any device capable of supplying welding, plasma cutting, and/or induction heating power, as well as control circuitry and other ancillary circuitry associated therewith.
Welding-type power supplies receive power and convert or transform that power into power suitable for welding. Known types of power supplies include transformer based power supplies and switched based power supplies, including buck, boost, PWM, chopper and other topologies. The input power is usually utility power or derived from an engine/generator. Welding power supplies with utility or engine power have been commercially successful for many years, although traditionally power supplies were designed to receive a limited range of input power voltages from either utility or an engine (but not both). Recently, power supplies have become more versatile and can be used for a variety of processes and receive a wide range of input voltages from either a utility source or an engine. (See, e.g. U.S. Pat. No. 6,239,407, hereby incorporated by reference).
Attempts have been made to power welders with other sources such as batteries or vehicles. However, battery power welders have been of limited application because battery power does not lend itself to long term high power outputs such as welding, and the control of such systems has not been able to provide a versatile, useful, welding source. Additionally, battery welders have not provided an AC auxiliary output (i.e., a 115 or 230 volt output that can be used as a substitute for utility power for tools, lights, etc.).
There are numerous applications for welding that are remote from a source of power. Many of these welding applications also have a need for AC auxiliary power (such as 115 VAC or 230 VAC). The AC auxiliary power may be used to operate grinders, saws or other power tools used to prepare for welding, or used for other applications at the remote site. The requirement for welding power and/or AC auxiliary power may be for short, intermittent periods of time, but spread out over a duration of several hours or more.
Prior art systems provide welding power for such remote applications with an engine driven welder/generator. The engine driven welder/generator is often started and left running for the total duration of the welding task or other task requiring AC power, even though the demand for the welding power or AC power is of a limited sporadic nature. Prior art engine/generators often operate at a fixed RPM to provide the fixed frequency (50/60 Hz, e.g) AC auxiliary power. This may require the engine to run at a speed well above an idle speed to maintain 60 Hz AC power even though the total power demand can be quite low. This can lead to excess wear, fuel consumption, and noise.
Accordingly, AC aux power that does not require an engine to run at a fixed RPM is desirable. Such, a system preferably will be able to receive battery power as an input. Also, such a system will preferably be able to be used in a variety of applications, and will provide for charging the battery. Also, such a system will preferably provide an auxiliary output.
Welding-type systems have utility across a wide range of industries including manufacturing, construction, automotive, and service industries. Welding-type processes are often required at elevated heights, and where utility power is not available, such as for ship building, bridges, constructions, etc. An operator is often required to be elevated through the use of a lift, such as a boom lift or a scissor lift. Scissor lifts and boom lifts have many applications across many industries. Both lifts generally include a drive assembly attached to the base for positioning the lift and a power system having any one of an engine, a motor, a battery array, or combination thereof. The power system of the lift is connected to the drive assembly and moves the lift from location to location, as well as elevates the platform. A welding-type power supply that can be used with a dc power system on a vehicle is thus desirable.